The protagonist of the series. With a gentle appearance and slim profile, in many ways Haruka is the splitting image of his fraternal twin sister Sora. Personable and honest, he forges lasting friendships with remarkable ease. Haruka copes with the loss of his parents with a stout heart, burdened with the knowledge that the future of his delicate sister depends on him. As a result, he has a tendency to dote on his sister and worry about her constantly. He cannot swim either. The Kasugano siblings are well regarded around the village, as their grandfather was once a doctor there.

Yosuga no Sora is a romantic anime about two orphaned twins and their "unique bond". The brother twin, Haruka, is frequently running into beautiful girls at his school, much to the dismay of his twin sister Sora. Take a look at these gifs of the twins and classmates interactions.